The present invention relates to a device for enciphering and deciphering data to be written to or read from a hard disk.
The object of the invention is to provide a device by which, in an efficient manner and without expensive hardware and/or complex software, use can be made of existing hard disk storage units, for instance of the IDE type (IDE=Integrated Drive Electronics), and standardized computer types, for instance computers of the so-called AT type in cooperation with commercially available cipher ICs for encryption through the Data Encryption Standard (DES) algorithm.
A problem in the use of commercially available cipher ICs for encryption through the DES algorithm is that these ICs encrypt words of a width of 64 bits, whereas many computer standards function with words of a considerably lesser width, for instance a word width of 16 bits in the case of an AT computer. A drawback of previously proposed combinations of existing computer systems with commercially available cipher ICs is that the processing of data during writing to or reading from a hard disk storage unit is very slow and that additional software is required for controlling the cipher IC and the disk storage unit.